Golf club head with selectively detachable face

ABSTRACT

A golf club head includes a polymeric body and a metallic cup face that are coupled together through a plurality of mechanical fasteners. The cup face has a ball striking portion that defines a hitting surface and a side-wall that extends from a perimeter of the ball striking portion. The plurality of mechanical fasteners extend through the side-wall and operative to removably secure the face to the body. When assembled, the body and the face define a closed volume.

TECHNICAL FIELD

The present invention relates generally to a golf club head having a selectively detachable face.

BACKGROUND

A golf club may generally include a club head disposed on the end of an elongate shaft. During play, the club head may be swung into contact with a stationary ball located on the ground in an effort to project the ball in an intended direction and with a desired vertical trajectory.

Many design parameters must be considered when forming a golf club head. For example, the design must provide enough structural resilience to withstand repeated impact forces between the club and the ball, as well as between the club and the ground. The club head must conform to maximum size requirements set by different rule setting associations, and the face of the club must not have a coefficient of restitution above a predefined maximum (measured according to applicable standards). Assuming that certain predefined design constraints are satisfied, a club head design is typically quantified by the magnitude and location of the center of gravity, as well as the head's moment of inertia about the center of gravity and/or the shaft.

The club's moment of inertia relates to the club's resistance to rotation (particularly during an off-center hit), and is often perceived as the club's measure of “forgiveness.” In typical driver designs, high moments of inertia are desired to reduce the club's tendency to push or fade a ball. Achieving a high moment of inertia generally involves placing mass as close to the perimeter of the club as possible (to maximize the moment of inertia about the center of gravity), and as close to the toe as possible (to maximize the moment of inertia about the shaft).

While the moment of inertia affects the forgiveness of a club head, the location of the center of gravity behind the club face (and above the sole) generally affects the trajectory of a shot for a given face loft angle. A center of gravity that is positioned as far rearward (away from the face) and as low (close to the sole) as possible typically results in a ball flight that has a higher trajectory than a club head with a center of gravity placed more forward and/or higher.

While a high moment of inertia is obtained by increasing the perimeter weighting of the club head, an increase in the total mass/swing weight of the club head (i.e., the magnitude of the center of gravity) has a strong, negative effect on club head speed and hitting distance. Said another way, to maximize club head speed (and hitting distance), a lower total mass is desired; however a lower total mass generally reduces the club head's moment of inertia (and forgiveness).

In the tension between swing speed (mass) and forgiveness (moment of inertia), it may be desirable to place varying amounts of mass in specific locations throughout the club head to tailor a club's performance to a particular golfer or ability level. In this manner, the total club head mass may generally be categorized into two categories: structural mass and discretionary mass.

Structural mass generally refers to the mass of the materials that are required to provide the club head with the structural resilience needed to withstand repeated impacts. Structural mass is highly design-dependant, and provides a designer with a relatively low amount of control over specific mass distribution. On the other hand, discretionary mass is any additional mass that may be added to the club head design for the sole purpose of customizing the performance and/or forgiveness of the club. In an ideal club design, the amount of structural mass would be minimized (without sacrificing resiliency) to provide a designer with a greater ability to customize club performance, while maintaining a swing weight that is expected by the consumer.

SUMMARY

A golf club head includes a body formed from a polymeric material and a face formed from a metallic material. The body includes a crown, a sole, and a hosel. The face is removably attached to the body via a plurality of mechanical fasteners, and, when attached, the body and the face define a closed volume.

In one configuration, the face is a cup face that includes a ball striking portion and a side-wall extending from a perimeter of the ball striking portion. The ball striking portion and the side-wall define a recess that is configured to receive a portion of the body that may include a portion of the crown and a portion of the sole. The ball striking portion defines a strike face that is opposite the recess.

The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view of a golf club having a detachable face.

FIG. 2 is a schematic exploded view of the golf club head of FIG. 1.

FIG. 3 is a schematic cross sectional view of the golf club head of FIG. 1, taken along line 3-3.

FIG. 4 is a schematic cross sectional view of the golf club head of FIG. 1, taken along line 3-3 and in an opposite direction from FIG. 3.

DETAILED DESCRIPTION

Referring to the drawings, wherein like reference numerals are used to identify like or identical components in the various views, FIG. 1 illustrates a schematic perspective view of a wood-type golf club head 10 (i.e., “club head 10”) that generally includes a face portion 12 (i.e., the “face 12”) and a body portion 14 (i.e., the “body 14”). As generally illustrated in FIG. 2, the club head 10 may be mounted on the end of an elongate shaft 16, which may be gripped and swung by a user to impart a generally arcuate motion to the club head 10.

The face 12 of the club head 10 may generally include a ball-striking portion 18 having a hitting surface 20 that is intended to contact a golf ball during a normal swing. The hitting surface 20 may be a planar surface, or may have a slight convex/arcuate curvature (i.e. bulge and/or roll) that extends out from the club head 10. Additionally, as is commonly understood, the hitting surface 20 may be disposed at an angle to a vertical plane when the club is held in a neutral hitting position. This angle may be generally referred to as the loft angle or slope of the club. Wood-type club heads (including hybrid woods), such as illustrated in FIGS. 1-4, may most commonly have a loft angle of from about 8.5 degrees to about 24 degrees, though other loft angles are possible and have been commercially sold.

The body 14 of the club head 10 may generally be configured to support the face 12 and to provide a connection means between the face 12 and the elongate shaft 16. Referring again to FIG. 1, the body 14 may generally include a lower portion 22 (i.e., a “sole 22”) and an upper portion 24 (i.e., a “crown 24”). For the purpose of this description, the crown 24 may meet the sole 22 where the surface has a vertical tangent when the club head 10 is held in a neutral hitting position (i.e., a position where the shaft 16 is maintained entirely in a vertical plane and at a prescribed lie angle relative to a horizontal ground plane). In practice, a portion of the sole 22 near this transition point may also be referred to as the skirt 26. Finally, the club head 10 includes a hosel 28 that is configured to receive a shaft adapter and/or otherwise couple with the elongate shaft 16.

Detachable Cup Face

In one embodiment, the face 12 may have a cup-face style construction/design that includes a side-wall portion 38 extending from the perimeter of the ball-striking portion 18 toward the rear of the club head 10. The side-wall portion 38 and the ball-striking portion 18 may form a concave recess opposite the hitting surface 20 (i.e., having a cup-like appearance). Such a face construction enables the attachment point between the face 12 and the body 14 to be positioned behind the hitting surface 20. This is in contrast to other plate-like face constructions that require attachment at or around the perimeter of the hitting surface 20, itself. By positioning the attachment apart from the hitting surface, it is less likely that any attachment means (e.g., a weld, screw, or the like) would influence the flexural properties of the hitting surface 20. Conversely, in plate-like face constructions, weld beads and/or thermal tempering may directly affect the stiffness of the perimeter of the hitting surface 20.

Additionally, the face 12 may be formed from a material that may suitably withstand a direct impact with a golf ball. While such a material may preferably be metallic, such as a titanium alloy, in other embodiments, it may include one or more polymer layers, carbon-fiber layups, or the like. In still other embodiments, the face 12 may be entirely formed from a polyermic material that is designed to withstand large impact loads.

FIG. 3 generally illustrates a schematic cross-sectional view 40 taken along section 3-3 shown in FIG. 1. As shown, the face 12 and the body 14 may cooperate to surround and/or define an internal volume/cavity 44. Additionally, the cup face 12 may be dimensioned to allow a portion of the body 14 to be received and selectively secured within the concave recess formed by the cup face 12. In one configuration, the face 12 may be secured to the body 14 via one or more mechanical fasteners 46 that extend through the sidewall 38 and into the body 14. The mechanical fasteners 46 may include one or more screws, cams, or other such devices that may restrain the face 12 from being removed from the body 14 while in place, though may provide a non-destructive means of separating the face 12 and the body 14 when removed.

Enabling removal of the face 12 may provide certain benefits that are not found in conventional fixed face designs. For example, interchangeable faces may be used to selectively vary at least one geometric face parameter such as, for example, the face angle, the loft angle, the bulge radius, or the roll radius. Likewise, interchangeable faces may also be used to selectively vary at least one dynamic response parameter such as, for example, the club head center of gravity, the total mass of the club head, or the coefficient of restitution of the face. Finally, interchangeable faces may also be used to alleviate durability concerns that may result from certain thin face designs.

With regard to altering at least one geometric face parameter of the club head 10, different users may benefit from differing face geometries according to their swing characteristics. For example, a user that has a tendency to slice their drive, may benefit from a face angle that has a draw bias. Likewise, a user with a slow swing speed may benefit from a greater loft angle than a user with a fast swing speed. Finally, a user that has a tendency to impact the ball away from the center of the face may benefit from a clubface that has an increased bulge radius or roll radius.

While the geometric face parameters may relate to the specific geometry of the club face 12, the dynamic response parameters may affect the behavior of the club head 10 throughout the swing and impact. Different faces may be specifically designed to alter the location of the center of gravity of the club head 10 or alter various moments of inertia of the club head. This may be accomplished by changing the distribution of weight between the heel and toe, between the crown and sole and/or around the perimeter of the hitting surface 20. For example, placing additional mass toward the outer perimeter of the club head 10 and/or toward the toe may increase the club head's moment of inertia (resistance to twisting). Likewise, placing additional weight toward the sole may lower the club head's center of gravity, which generally increases launch angle and spin. Additionally, by enabling removal of the face 12, weights may be selectively placed within the body, such as by affixing to a predetermined weight port.

Finally, from a durability perspective, a removable face may allow thinner hitting surfaces to be used without as much concern for the long term durability of the club head 10. The durability of a face 10 is typically measured by successively impacting the face with a predetermined number of golf balls traveling at a high rate of speed. The test is often performed at various locations across the club head 10, and the club head must not show any signs of structural damage following a test. In fixed face designs, the club face is often overdesigned and/or made significantly thicker to pass such a durability test at professional tour-level swing speeds. By providing a means to replace a damaged face, the durability standards may be reduced to permit thinner face designs. Alternatively, faces may be provided to more closely correlate with the end user's actual swing speed rather than always overdesigning the face to satisfy tour-level conditions.

Polymeric Body

To reduce structural mass beyond what is economically viable with metal alloys, the body 14 of the club head 10 may be formed from a polymeric material, which is less dense than traditional metal body designs. To promote design flexibility, the polymeric material may be molded into shape using any of the number of molding techniques, such as, injection molding, compression molding, blow molding, or the like. While weight savings and design flexibility are important, the polymeric material must also be strong enough to withstand the stress that is experienced when the club head 10 impacts a ball. To accomplish this, it is preferable to use a material that has a tensile strength of greater than about 200 MPa (according to ASTM D638), or more preferably greater than about 250 MPa. Additionally, for ease of molding, if the polymeric material is filled, then it desirably has a resin content of greater than about 50%, or even greater than about 55% by weight. One such material may include, for example, a thermoplastic aliphatic or semi-aromatic polyamide that is filled with chopped fiber, such as chopped carbon fiber or chopped glass fiber. Other materials may include polyimides, polyamide-imides, polyetheretherketones (PEEK), polycarbonates, engineering polyurethanes, and/or other similar materials. In one configuration, the polymeric body 14 may be devoid of any metallic support structure or frame that directly couples with the face 12.

In one configuration, the polymeric body 14 may be integrally formed as a single, continuous piece. An integral design may have strength benefits by reducing seams, weld lines, or other parting lines, however it may also increase the complexity of the molding process. In other configurations, the body 14 may be formed from multiple components that are fused together through, for example, ultrasonic welding, laser welding, or the use of adhesives. For example, in one embodiment, the sole 22, crown 24, and hosel 28 may each be formed through a separate molding process and then subsequently fused together.

As noted above, and shown in the figures, the hosel 28 may be formed from a polymeric material, similar to the crown 24 and the sole 22. Referring to FIG. 1, the hosel 28 generally defines a recess 60 that is configured to receive a golf club shaft 16 and/or a shaft adapter 62. In one configuration, the hosel 28 includes a plurality of splines 64 disposed on an inward-facing surface that surrounds the recess 60. The splines 64 are intended to inhibit any relative rotation between the shaft 16 and the golf club head 10 once the shaft 16 or shaft adapter 62 is inserted within the recess 60.

In one configuration, the hosel 28 may be formed through similar molding techniques as the remainder of the body, and using similar polymeric materials. When formed in this manner, the hosel 28 may avoid any need for metallic inserts to be secured within the recess 60. More specifically, by having flexural characteristics that more closely match those of the shaft adapter 62 and or certain composite shafts, boundary layer incompatibilities may be minimized, which reduces wear at the interface and increases durability.

In general, the body 14 of the present design accomplishes four objectives: supporting the face 12; structurally coupling the face 12 with the shaft via the hosel 28; moving the center of gravity of the club head 10 rearward of the face 12 and/or hitting surface 20; and, increasing the moment of inertia of the club head 10 to allow the club head 10 to strike through the ball and minimize any twisting. A polymer body construction may accomplish the first two objectives at a lower required structural weight than conventional metal body construction. In doing so, the polymer body construction may provide a greater amount of discretionary weight that can be strategically placed about the club head (to better accomplish the last two objectives).

In one configuration, to secure the face 12 to the body 14, each of the plurality of mechanical fasteners 46 may be either directly received by the polymer, or may be received by an inlaid object, such as a metal insert. The mechanical fasteners 46 may be directly received, for example, by providing a threaded recess directly in the polymer. If inserts are used, then each insert may have, for example, a threaded internal section that receives one fastener. In one configuration, each insert may be separately placed in the body such that the polymeric material surrounds each insert separately and/or such that the inserts are coupled to each other only via the polymer.

For weighting purposes, the polymer body 14 may include one or more discretionary weights, such as captured metallic inserts, that may be used to alter the magnitude and/or position of the club head center of mass and/or one or more moments of inertia of the club head 10. These discretionary weights are located apart from the face 12 and coupled to the face 12 via the polymeric material. In one configuration, the discretionary weights are separated from the face 12 by a minimum distance that is, for example, greater than about 10 mm. In one embodiment, as shown in FIG. 3, the discretionary weight may include a metallic band 70 that is disposed about a portion of the perimeter of the club head 10 (e.g., where the sole 22 meets the crown 24). Such a weight may increase the moment of inertia about a vertical axis, and may move the center of mass rearward of the face. In one embodiment, this band 70 may have a varying thickness to enable more precise control over the location of the center of gravity and the various moments of inertia. In other embodiments, the discretionary weight may include a doped portion of the polymeric body 14, a weighted medallion that is adhered to the inside or outside of the body 14, or a screw-in or twist-lock removable weight.

In still other configurations, the metallic inserts may include one or more metal objects, such as plates or discs that are overmolded by the polymer within the sole 22, crown 24, intersitital space, or other portions of the body 14. Due to the cost effective nature of polymer molding, a manufacturer may use these techniques to produce a plurality of club head bodies that each have a different mass and/or mass distribution. In still other configurations, the metallic inserts may have a threaded portion that can receive a screw-in style weight.

Club Customization

Using the present design, a club head may be assembled in a manner that is specific to the characteristics of a user's swing. More specifically, constructing a club head may include the steps of: selecting a face 12 from a plurality of faces, each of the plurality of faces having one or more different parameters selected from the loft angle, the face angle, the bulge radius, the roll radius, the mass, the audible impact frequency, and the coefficient of restitution across the club face; selecting a body 14 from a plurality of bodies, each of the plurality of bodies having a different weight parameter selected from a total mass and a mass distribution.

In one configuration, for example, the plurality of faces may include at least three different faces, each having a different coefficient of restitution intended for a user with a different swing speed (e.g., slow, average, fast). In another configuration, the plurality of faces may include at least nine different faces, with each face having one of three different coefficient of restitutions and one of three different face orientation profiles (e.g., low, medium, and high loft, or draw, neutral, fade biased face angle).

In a similar manner, in one configuration, the plurality of bodies may include at least three bodies, each having a different total mass intended for users of differing swing speeds (e.g., light, average, and heavy bodies, intended for users of slow, average, and fast swing speeds, respectively). In another configuration, the plurality of bodies may include at least nine different bodies, with each body having one of three different total masses and one of three different weight biasing profiles (e.g, toe, center, and heal-biased weighting; or face, mid, and rear-biased weighting).

In another embodiment, a shaft adapter such as described in U.S. Patent Application No 2013/0324291 to Arluna et al, which is incorporated by reference in its entirety, may be used to vary the loft angle and face angle, while the plurality of faces may be used to vary the coefficient of restitution, and the plurality of bodies may be used to vary the total club head mass and/or one or more dynamic parameters such as a dynamic loft or a ball-spin tendency.

In addition to providing different weight profiles, the cosmetic appearance may also be more substantially varied through the polymer body construction. In general, polymer molding techniques can provide a more complex and detailed design than metal fabrication techniques are capable of Additionally, for a similar design, polymer molding is generally less expensive than metal fabrication. As such, the plurality of bodies may also include varying cosmetic designs that range from conservative (i.e., a generally uniform shell) to aggressive (i.e., including many recesses, accent ribs, or colored panels).

By permitting a mix and match style of club head creation, retailers may be able to offer a more customized golf club that is tailored specifically to a user's preferences or swing. This interchangeable component structure also can eliminate the need to inventory every possible combination of components.

While various embodiments have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims.

“A,” “an,” “the,” “at least one,” and “one or more” are used interchangeably to indicate that at least one of the item is present; a plurality of such items may be present unless the context clearly indicates otherwise. All numerical values of parameters (e.g., of quantities or conditions) in this specification, including the appended claims, are to be understood as being modified in all instances by the term “about” whether or not “about” actually appears before the numerical value. “About” indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; about or reasonably close to the value; nearly). If the imprecision provided by “about” is not otherwise understood in the art with this ordinary meaning, then “about” as used herein indicates at least variations that may arise from ordinary methods of measuring and using such parameters. In addition, disclosure of ranges includes disclosure of all values and further divided ranges within the entire range. Each value within a range and the endpoints of a range are hereby all disclosed as separate embodiment. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated items, but do not preclude the presence of other items. As used in this specification, the term “or” includes any and all combinations of one or more of the listed items. When the terms first, second, third, etc. are used to differentiate various items from each other, these designations are merely for convenience and do not limit the items. 

1. A golf club head comprising: a body including a crown, a sole, and a hosel, each formed from a polymeric material; and a face formed from a metallic material, the face including: a ball striking portion defining a hitting surface; and a side-wall extending from a perimeter of the ball striking portion; wherein the ball striking portion and the side-wall define a recess that is configured to receive a portion of the body; and wherein the hitting surface that is opposite the recess; a plurality of mechanical fasteners extending through the side-wall and operative to removably secure the face to the body; and wherein the body and the face define a closed volume.
 2. (canceled)
 3. The golf club head of claim 1, wherein the body includes a plurality of metal inserts, each insert being operative to receive one of the plurality of mechanical fasteners.
 4. The golf club head of claim 3, wherein each of the plurality of metal inserts are surrounded by the polymeric material.
 5. The golf club head of claim 4, wherein the plurality of metal inserts are coupled to each other only through the polymeric material.
 6. The golf club head of claim 1, further comprising a metallic weighting element embedded within the polymeric material and positioned apart from the face by a distance of greater than about 10 mm.
 7. The golf club head of claim 6, wherein the metallic weighting element includes a band of material disposed proximate a perimeter of the club head and between the crown and the sole.
 8. The golf club head of claim 1, wherein the polymeric material is a filled, molded polymer having a tensile strength of greater than about 200 MPa.
 9. The golf club head of claim 8, wherein the filled, molded polymer includes an aliphatic polyamide filled with a chopped carbon fiber; and wherein the metallic material includes a titanium alloy.
 10. The golf club head of claim 1, wherein the plurality of mechanical fasteners includes a first plurality of fasteners and a second plurality of fasteners; and wherein each fastener of the first of the plurality of fasteners extends through the crown, and wherein each fastener of the second of the plurality of fasteners extends through the sole.
 11. A golf club head comprising: a body formed from a polymeric material, the body including a crown, a sole, and a hosel; and a cup face formed from a metallic material that is secured to the body using a plurality of mechanical fasteners; wherein the body and the cup face define a closed volume; and wherein the cup face is removable from the body by removing each of the plurality of mechanical fasteners.
 12. The golf club head of claim 11, wherein the cup face includes: a ball striking portion defining a hitting surface; and a side-wall extending from a perimeter of the ball striking portion in a direction opposite the hitting surface and overlapping a portion of the crown and a portion of the sole; and wherein the plurality of mechanical fasteners extend through the side-wall.
 13. The golf club head of claim 11, wherein each of the crown, the sole, and the hosel are formed from the polymeric material.
 14. The golf club head of claim 11, wherein the body includes a plurality of metal inserts, each insert being operative to receive one of the plurality of mechanical fasteners.
 15. The golf club head of claim 14, wherein each of the plurality of metal inserts are surrounded by the polymeric material.
 16. The golf club head of claim 15, wherein the plurality of metal inserts are coupled to each other only through the polymeric material.
 17. The golf club head of claim 11, further comprising a metallic weighting element embedded within the polymeric material and positioned apart from the face by a distance of greater than about 10 mm.
 18. The golf club head of claim 17, wherein the metallic weighting element includes a band of material disposed proximate a perimeter of the club head and between the crown and the sole.
 19. The golf club head of claim 11, wherein the polymeric material is a filled, molded polymer having an ultimate yield strength of greater than about 200 MPa.
 20. The golf club head of claim 19, wherein the filled, molded polymer includes an aliphatic polyamide filled with a chopped carbon fiber; and wherein the metallic material includes a titanium alloy. 